Windows update problems

One of my machines got stuck on checking for updates for over twenty mins so I used brinks tutorial to reset the windows update. It went through but after a reboot Microsoft defender refuses to start with an error about the security client on each restart now and a refusal to open manually. Plus the Windows update still gets stuck on checking for updates and now the App Store won't finishing checking for updates. Seems I am in quite a pickle. Any advice?

am trying a system restore point I created last week but it's taking ages on initialising and I'm not holding much hope for this working out

System restore took an age but seems to have restored normality. Will keep an eye on this though.

i knew something was up before I ran the initial check for updates. Could see the cpu meter constantly at 30 and task manager had windows modules installer/worker (or whatever it's called) as the culprit. So when I checked for updates it wasn't finishing the check presumably because of this task it was busy with. Maybe I should of left it alone for a while to complete whatever it was doing - I guess resetting windows update in this particular instance wasn't the best move

but this is what frustrates me with Windows 10, the unpredictability of it. It's almost as if it's dangerous to leave windows idle for long as it can then get up to all sorts of mischief in the background. I'm sure this is what caused my original woes, some kind of background process that was taking an age to complete and blocking windows update from finishing its check